LETTERS TO EDITOR
Comparison of Etiological Agents and Resistance Patterns of the Pathogens Causing Community Acquired and Hospital Acquired Urinary Tract Infections Sir, Urinary tract infections (UTIs) are one of the most common infections encountered by physicians. The study was carried out to know the common bacteria causing UTI and their resistance pattern to commonly prescribed antibiotics at our hospital. Patients were assigned into two categories: one group comprising of urine samples from patients admitted in the hospital for at least 48 h (hospital acquired urinary tract infection or HA-UTI), and another group comprising of urine samples from patients visiting the hospital on an outpatient basis or admitted for lesser than 48 h (community acquired urinary tract infection or CA-UTI).[1]
Urine samples (1,378) were collected between 1st January 2012 and 30th June 2012 from cases suspected of having CA-UTI and HA-UTI. Patients were instructed to submit first morning mid stream clean catch urine (CCMS) samples; from catheterized indoor patients samples were collected by healthcare workers after disinfecting the port with 70% alcohol and then aspirating urine through the port with a sterile needle and syringe. The samples were processed as per standard procedures; antibiotic susceptibility testing was performed by the Kirby Bauer disc diffusion method as per Clinical and Laboratory Standards Institute (CLSI) recommendations.[2,3] Statistical analysis was done using Fisher’s exact test. P value lesser than 0.05 was considered as statistically significant. Results obtained in this study are shown in Tables 1 and 2. Of the 1,378 urine samples processed during the study period, 340 (24.7%) yielded urinary pathogens, of which 324 had significant bacteriuria and 16 had Candiduria. Gram-negative bacilli accounted for 281 (82%), grampositive cocci for 43 (13%) and Candida sp. for 16 (5%) of the total pathogens. Escherichia coli was the predominant pathogen in both CA-UTI and HA-UTI cases. The next top 5 uropathogens after E. coli , causing HA-UTI in our
Table 1: Frequency, percentage, and P-value of resistant gram-negative bacteria isolated from CA-UTI versus HA-UTI patients Bacteria
Group of antibiotic (as per CLSI Guidelines)
Antibiotic
CA/HA number of isolates First line drugs (group A and U)
Second line drugs (group B)
Third line drugs (group C)
Citrobacter sp.
Klebsiella sp.
Enterobacter sp.
Proteus sp.
*Pseudomonas aeruginosa
132/48
18/10
17/11
9/2
7/1
4/21
61/40 (0.04)
8/8 (1.00)
8/9 (0.92)
4/2 (0.40)
3/1 (0.97)
2/17 (0.02)
AMP
85/100 (0.02)
83/100 (0.02)
65/91 (0.02)
89/100 (0.03)
86/100 (0.02)
—
GEN
51/71 (0.04)
56/70 (0.08)
41/82 (0.009)
33/67 (0.01)
71/67 (0.59)
50/90 (0.008)
OFL
77/94 (0.03)
56/80 (0.02)
53/91 (0.009)
33/67 (0.01)
71/67 (0.59)
50/86 (0.01)
NOR
80/94 (0.04)
72/90 (0.04)
59/91 (0.01)
33/67 (0.01)
71/67 (0.59)
50/86 (0.01)
NIT
27/33 (0.34)
22/50 (0.02)
59/55 (0.63)
44/100 (0.004)
100/100 (1.00)
—
AMK
5/23 (0.02)
33/60 (0.02)
18/45 (0.02)
11/33 (0.02)
43/33 (0.15)
50/86 (0.01)
AMC
84/100 (0.02)
78/100 (0.01)
82/91 (0.09)
89/100 (0.03)
86/100 (0.02)
—
CEP
72/90 (0.03)
67/100 (0.008)
53/82 (0.02)
44/67 (0.03)
43/67 (0.03)
75/90 (0.04)
CET
78/94 (0.03)
72/100 (0.009)
59/91 (0.01)
44/67 (0.03)
57/67 (0.15)
—
CIP
78/94 (0.03)
67/90 (0.02)
59/91 (0.01)
33/67 (0.01)
86/67 (0.03)
50/86 (0.01)
ERT
8/23 (0.04)
39/50 (0.13)
6/64 (0.004)
0/33 (0.008)
43/33 (0.15)
—
IMP
4/4 (1.00)
17/10 (0.15)
6/18 (0.05)
0/33 (0.008)
29/33 (0.59)
0/62 (0.004)
MER
15/23 (0.15)
44/40 (0.63)
24/55 (0.02)
0/33 (0.008)
29/33 (0.59)
50/76 (0.02)
COT
54/69 (0.07)
72/70 (0.88)
35/73 (0.01)
56/67 (0.12)
86/67 (0.03)
—
SAM
56/67 (0.12)
78/90 (0.06)
100/91 (0.03)
56/67 (0.12)
86/67 (0.03)
—
Percentage of total isolates (P value) Percentage of CA/HA bacteria resistant to (P value)
Escherichia coli
TZP
31/33 (0.88)
67/70 (0.75)
59/64 (0.48)
33/67 (0.01)
43/67 (0.03)
50/71 (0.04)
PIP
79/100 (0.01)
61/80 (0.04)
53/91 (0.009)
12/67 (0.005)
43/67 (0.03)
50/76 (0.02)
AZT
76/92 (0.03)
56/100 (0.006)
59/91 (0.01)
44/67 (0.03)
29/67 (0.01)
75/90 (0.04)
CAZ
80/94 (0.04)
72/100 (0.009)
59/100 (0.006)
44/67 (0.03)
57/67 (0.15)
75/90 (0.04)
TCY
46/72 (0.02)
39/100 (0.004)
41/82 (0.009)
67/67 (1.00)
71/67 (0.59)
—
12/6 (0.14)
6/10 (0.27)
12/0 (0.03)
0/33 (0.008)
14/33 (0.03)
—
†
TIG
P value of less than 0.05 is considered as significant; *The grouping is not applicable for Pseudomonas aeruginosa; †Tigecycline is not a group C drug as per CLSI guidelines; AMP: Ampicillin; GEN: Gentamicin; OFL: Oflaxacin; NOR: Norfloxacin; NIT: Nitrofurantoin; AMK: Amikacin; AMC: Amoxycillin-Clavulanic acid; CEP: Cefepime; CET: Cefotaxime; CIP: Ciprofloxacin; ERT: Ertapenem; IMP: Imipenem; MER: Meropenem; COT: Cotrimoxazole; SAM: Ampicillin-sulbactam; TZP: Piperacillin-tazobactam; PIP: Piperacillin; AZT: Aztreonam; CAZ: Ceftazidime; TCY: Tetracycline; TIG: Tigecycline
Journal of Global Infectious Diseases / Jul-Sept 2014 / Vol-6 / Issue-3
135
Letters to Editor
Table 2. Frequency, percentage and P-value of resistant gram-positive bacteria isolated from CA-UTI versus HA-UTI patients Bacteria
Group of antibiotic (as per CLSI Guidelines)
Enterococcus sp.
CA/HA number of isolates
Staphylococcus aureus
16/8
14/5
5/3
7/7 (1.00)
6/4 (0.55)
2/3 (0.75)
PEN
87/100 (0.02)
86/100 (0.02)
100/0 (0.002)
NOR
25/100 (0.003)
29/60 (0.02)
0/67 (0.003)
NIT
75/62 (0.08)
64/40 (0.03)
60/33 (0.02)
COT
—
36/40 (0.62)
40/67 (0.02)
OXA
—
21/60 (0.01)
40/67 (0.02)
FOX
—
21/60 (0.01)
40/67 (0.02)
AMP
62/62 (1.00)
—
—
CIP
81/100 (0.02)
—
—
Second line drugs (group B)
LIN
0/0 (1.00)
0/0 (1.00)
0/0 (1.00)
VAN
6/0 (0.05)
0/0 (1.00)
0/0 (1.00)
Third line drugs (group C)
GEN
75/62 (0.08)
71/40 (0.02)
60/33 (0.02)
Percentage of total isolates (P value) Percentage of CA/HA bacteria resistant to (P value)
Staphylococcus sp.
First line drugs (group A and U)
CIP
—
71/60 (0.12)
60/67 (0.28)
*TIG
0/12 (0.03)
14/20 (0.24)
20/33 (0.07)
*TCP
44/12 (0.01)
—
—
P value of less than 0.05 is considered as significant; *Tigecycline and Teicoplanin are not group C drugs as per CLSI guidelines PEN: Penicillin; NOR: Norfloxacin; NIT: Nitrofurantoin; COT: Cotrimoxazole; OXA: Oxacillin; FOX: Cefoxitin; AMP: Ampicillin; CIP: Ciprofloxacin; LIN: Linezolid; VAN: Vancomycin; GEN: Gentamicin; CIP: Ciprofloxacin; TIG: Tigecycline; TCP: Teicoplanin
hospital were Pseudomonas aeruginosa 21(17%); Candida sp. 14 (11.0%); Klebsiella sp. 11 (9%); Citrobacter sp. 10 (8%); and Enterococcus sp. 8 (7%), while those causing CA-UTI were Citrobacter sp. 18(8%); Klebsiella pneumoniae 17(8%); Enterococcus sp. 16(7%); Staphylococcus sp. 14 (6%) and Enterobacter sp. 9 (4%). E. coli was statistically associated more with CA-UTI and P. aeruginosa was statistically associated more with HA-UTI. Resistance to ampicillin was more significantly associated with HA-UTI than CA-UTI among all the gram-negative pathogens. In case of P. aeruginosa, resistance to ceftazidime, cefepime, and aztreonam were more significantly associated with HA-UTI than CA-UTI. Among Staphylococcus aureus isolates, resistance was more significantly associated with HA-UTI than CA-UTI against cefoxitin, co-trimoxazole, and norfloxacin. Our data indicates that E. coli is still the most frequent uro-pathogen causing UTI in the community and hospital settings, which is consistent with the literature.[4] The resistance rates of the isolates were significantly lower in outpatients than those of inpatients, a finding which is consistent with observations all over the world.[5] Ampicillin, amoxicillin-clavulanic acid, TMP-SMX and ciprofloxacin did not have good in vitro coverage for many of the uro-pathogens isolated in this study. Nitrofurantoin is the only oral agent that remains relatively active against most uro-pathogens. Carbapenems, piperacillin-tazobactam, and amikacin showed good in vitro coverage of the uro-pathogens isolated in this study. 136
Nishat H Ahmed, Tabish Hussain1, Indu Biswal Department of Laboratory Medicine, Delhi State Cancer Institute, 1Proteomics and Structural Biology Unit, Institute of Genomics and Integrative Biology, New Delhi, India Address for correspondence: Dr. Nishat Hussain Ahmed, E-mail: [email protected],
REFERENCES 1.
2.
3.
4.
5.
Garner JS, Jarvis WR, Emori TG, Horan TC, Hughes JM. CDC Definitions for Nosocomial Infections. In: Olmsted RN, editor. APIC Infection control and applied epidemiology: Principles and Practice. St Louis: Mosby; 1996. p. A1- 20. Infections of the Urinary Tract. In: Forbes BA, Sahm DF, Weissfeld AS, editors. Bailey and Scott’s Diagnostic Microbiology. 12th ed. St. Louis Missouri: Mosby; 2007. p. 842-55. Clinical and Laboratory Standards Institute. Performance Standards for Antimicrobial Susceptibility Testing. 22nd informational supplement. Wayne: CLSI; 2012. Benwan KA, Sweigh NA, Rotimi VO. Etiology and susceptibility patterns of community- and hospital acquired urinary tract infections in a general hospital in Kuwait. Med Princ Pract 2010;19:440-6. Gupta K, Scholes D, Stamm WE. Increasing prevalence of antimicrobial resistance among uropathogens causing acute uncomplicated cystitis in women. JAMA 1999;281:736-8. Access this article online Quick Response Code: Website: www.jgid.org
DOI: 10.4103/0974-777X.138515
Journal of Global Infectious Diseases / Jul-Sept 2014 / Vol-6 / Issue-3
Copyright of Journal of Global Infectious Diseases is the property of Medknow Publications & Media Pvt. Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
Comparison of Etiological Agents and Resistance Patterns of the Pathogens Causing Community Acquired and Hospital Acquired Urinary Tract Infections Sir, Urinary tract infections (UTIs) are one of the most common infections encountered by physicians. The study was carried out to know the common bacteria causing UTI and their resistance pattern to commonly prescribed antibiotics at our hospital. Patients were assigned into two categories: one group comprising of urine samples from patients admitted in the hospital for at least 48 h (hospital acquired urinary tract infection or HA-UTI), and another group comprising of urine samples from patients visiting the hospital on an outpatient basis or admitted for lesser than 48 h (community acquired urinary tract infection or CA-UTI).[1]
Urine samples (1,378) were collected between 1st January 2012 and 30th June 2012 from cases suspected of having CA-UTI and HA-UTI. Patients were instructed to submit first morning mid stream clean catch urine (CCMS) samples; from catheterized indoor patients samples were collected by healthcare workers after disinfecting the port with 70% alcohol and then aspirating urine through the port with a sterile needle and syringe. The samples were processed as per standard procedures; antibiotic susceptibility testing was performed by the Kirby Bauer disc diffusion method as per Clinical and Laboratory Standards Institute (CLSI) recommendations.[2,3] Statistical analysis was done using Fisher’s exact test. P value lesser than 0.05 was considered as statistically significant. Results obtained in this study are shown in Tables 1 and 2. Of the 1,378 urine samples processed during the study period, 340 (24.7%) yielded urinary pathogens, of which 324 had significant bacteriuria and 16 had Candiduria. Gram-negative bacilli accounted for 281 (82%), grampositive cocci for 43 (13%) and Candida sp. for 16 (5%) of the total pathogens. Escherichia coli was the predominant pathogen in both CA-UTI and HA-UTI cases. The next top 5 uropathogens after E. coli , causing HA-UTI in our
Table 1: Frequency, percentage, and P-value of resistant gram-negative bacteria isolated from CA-UTI versus HA-UTI patients Bacteria
Group of antibiotic (as per CLSI Guidelines)
Antibiotic
CA/HA number of isolates First line drugs (group A and U)
Second line drugs (group B)
Third line drugs (group C)
Citrobacter sp.
Klebsiella sp.
Enterobacter sp.
Proteus sp.
*Pseudomonas aeruginosa
132/48
18/10
17/11
9/2
7/1
4/21
61/40 (0.04)
8/8 (1.00)
8/9 (0.92)
4/2 (0.40)
3/1 (0.97)
2/17 (0.02)
AMP
85/100 (0.02)
83/100 (0.02)
65/91 (0.02)
89/100 (0.03)
86/100 (0.02)
—
GEN
51/71 (0.04)
56/70 (0.08)
41/82 (0.009)
33/67 (0.01)
71/67 (0.59)
50/90 (0.008)
OFL
77/94 (0.03)
56/80 (0.02)
53/91 (0.009)
33/67 (0.01)
71/67 (0.59)
50/86 (0.01)
NOR
80/94 (0.04)
72/90 (0.04)
59/91 (0.01)
33/67 (0.01)
71/67 (0.59)
50/86 (0.01)
NIT
27/33 (0.34)
22/50 (0.02)
59/55 (0.63)
44/100 (0.004)
100/100 (1.00)
—
AMK
5/23 (0.02)
33/60 (0.02)
18/45 (0.02)
11/33 (0.02)
43/33 (0.15)
50/86 (0.01)
AMC
84/100 (0.02)
78/100 (0.01)
82/91 (0.09)
89/100 (0.03)
86/100 (0.02)
—
CEP
72/90 (0.03)
67/100 (0.008)
53/82 (0.02)
44/67 (0.03)
43/67 (0.03)
75/90 (0.04)
CET
78/94 (0.03)
72/100 (0.009)
59/91 (0.01)
44/67 (0.03)
57/67 (0.15)
—
CIP
78/94 (0.03)
67/90 (0.02)
59/91 (0.01)
33/67 (0.01)
86/67 (0.03)
50/86 (0.01)
ERT
8/23 (0.04)
39/50 (0.13)
6/64 (0.004)
0/33 (0.008)
43/33 (0.15)
—
IMP
4/4 (1.00)
17/10 (0.15)
6/18 (0.05)
0/33 (0.008)
29/33 (0.59)
0/62 (0.004)
MER
15/23 (0.15)
44/40 (0.63)
24/55 (0.02)
0/33 (0.008)
29/33 (0.59)
50/76 (0.02)
COT
54/69 (0.07)
72/70 (0.88)
35/73 (0.01)
56/67 (0.12)
86/67 (0.03)
—
SAM
56/67 (0.12)
78/90 (0.06)
100/91 (0.03)
56/67 (0.12)
86/67 (0.03)
—
Percentage of total isolates (P value) Percentage of CA/HA bacteria resistant to (P value)
Escherichia coli
TZP
31/33 (0.88)
67/70 (0.75)
59/64 (0.48)
33/67 (0.01)
43/67 (0.03)
50/71 (0.04)
PIP
79/100 (0.01)
61/80 (0.04)
53/91 (0.009)
12/67 (0.005)
43/67 (0.03)
50/76 (0.02)
AZT
76/92 (0.03)
56/100 (0.006)
59/91 (0.01)
44/67 (0.03)
29/67 (0.01)
75/90 (0.04)
CAZ
80/94 (0.04)
72/100 (0.009)
59/100 (0.006)
44/67 (0.03)
57/67 (0.15)
75/90 (0.04)
TCY
46/72 (0.02)
39/100 (0.004)
41/82 (0.009)
67/67 (1.00)
71/67 (0.59)
—
12/6 (0.14)
6/10 (0.27)
12/0 (0.03)
0/33 (0.008)
14/33 (0.03)
—
†
TIG
P value of less than 0.05 is considered as significant; *The grouping is not applicable for Pseudomonas aeruginosa; †Tigecycline is not a group C drug as per CLSI guidelines; AMP: Ampicillin; GEN: Gentamicin; OFL: Oflaxacin; NOR: Norfloxacin; NIT: Nitrofurantoin; AMK: Amikacin; AMC: Amoxycillin-Clavulanic acid; CEP: Cefepime; CET: Cefotaxime; CIP: Ciprofloxacin; ERT: Ertapenem; IMP: Imipenem; MER: Meropenem; COT: Cotrimoxazole; SAM: Ampicillin-sulbactam; TZP: Piperacillin-tazobactam; PIP: Piperacillin; AZT: Aztreonam; CAZ: Ceftazidime; TCY: Tetracycline; TIG: Tigecycline
Journal of Global Infectious Diseases / Jul-Sept 2014 / Vol-6 / Issue-3
135
Letters to Editor
Table 2. Frequency, percentage and P-value of resistant gram-positive bacteria isolated from CA-UTI versus HA-UTI patients Bacteria
Group of antibiotic (as per CLSI Guidelines)
Enterococcus sp.
CA/HA number of isolates
Staphylococcus aureus
16/8
14/5
5/3
7/7 (1.00)
6/4 (0.55)
2/3 (0.75)
PEN
87/100 (0.02)
86/100 (0.02)
100/0 (0.002)
NOR
25/100 (0.003)
29/60 (0.02)
0/67 (0.003)
NIT
75/62 (0.08)
64/40 (0.03)
60/33 (0.02)
COT
—
36/40 (0.62)
40/67 (0.02)
OXA
—
21/60 (0.01)
40/67 (0.02)
FOX
—
21/60 (0.01)
40/67 (0.02)
AMP
62/62 (1.00)
—
—
CIP
81/100 (0.02)
—
—
Second line drugs (group B)
LIN
0/0 (1.00)
0/0 (1.00)
0/0 (1.00)
VAN
6/0 (0.05)
0/0 (1.00)
0/0 (1.00)
Third line drugs (group C)
GEN
75/62 (0.08)
71/40 (0.02)
60/33 (0.02)
Percentage of total isolates (P value) Percentage of CA/HA bacteria resistant to (P value)
Staphylococcus sp.
First line drugs (group A and U)
CIP
—
71/60 (0.12)
60/67 (0.28)
*TIG
0/12 (0.03)
14/20 (0.24)
20/33 (0.07)
*TCP
44/12 (0.01)
—
—
P value of less than 0.05 is considered as significant; *Tigecycline and Teicoplanin are not group C drugs as per CLSI guidelines PEN: Penicillin; NOR: Norfloxacin; NIT: Nitrofurantoin; COT: Cotrimoxazole; OXA: Oxacillin; FOX: Cefoxitin; AMP: Ampicillin; CIP: Ciprofloxacin; LIN: Linezolid; VAN: Vancomycin; GEN: Gentamicin; CIP: Ciprofloxacin; TIG: Tigecycline; TCP: Teicoplanin
hospital were Pseudomonas aeruginosa 21(17%); Candida sp. 14 (11.0%); Klebsiella sp. 11 (9%); Citrobacter sp. 10 (8%); and Enterococcus sp. 8 (7%), while those causing CA-UTI were Citrobacter sp. 18(8%); Klebsiella pneumoniae 17(8%); Enterococcus sp. 16(7%); Staphylococcus sp. 14 (6%) and Enterobacter sp. 9 (4%). E. coli was statistically associated more with CA-UTI and P. aeruginosa was statistically associated more with HA-UTI. Resistance to ampicillin was more significantly associated with HA-UTI than CA-UTI among all the gram-negative pathogens. In case of P. aeruginosa, resistance to ceftazidime, cefepime, and aztreonam were more significantly associated with HA-UTI than CA-UTI. Among Staphylococcus aureus isolates, resistance was more significantly associated with HA-UTI than CA-UTI against cefoxitin, co-trimoxazole, and norfloxacin. Our data indicates that E. coli is still the most frequent uro-pathogen causing UTI in the community and hospital settings, which is consistent with the literature.[4] The resistance rates of the isolates were significantly lower in outpatients than those of inpatients, a finding which is consistent with observations all over the world.[5] Ampicillin, amoxicillin-clavulanic acid, TMP-SMX and ciprofloxacin did not have good in vitro coverage for many of the uro-pathogens isolated in this study. Nitrofurantoin is the only oral agent that remains relatively active against most uro-pathogens. Carbapenems, piperacillin-tazobactam, and amikacin showed good in vitro coverage of the uro-pathogens isolated in this study. 136
Nishat H Ahmed, Tabish Hussain1, Indu Biswal Department of Laboratory Medicine, Delhi State Cancer Institute, 1Proteomics and Structural Biology Unit, Institute of Genomics and Integrative Biology, New Delhi, India Address for correspondence: Dr. Nishat Hussain Ahmed, E-mail: [email protected],
REFERENCES 1.
2.
3.
4.
5.
Garner JS, Jarvis WR, Emori TG, Horan TC, Hughes JM. CDC Definitions for Nosocomial Infections. In: Olmsted RN, editor. APIC Infection control and applied epidemiology: Principles and Practice. St Louis: Mosby; 1996. p. A1- 20. Infections of the Urinary Tract. In: Forbes BA, Sahm DF, Weissfeld AS, editors. Bailey and Scott’s Diagnostic Microbiology. 12th ed. St. Louis Missouri: Mosby; 2007. p. 842-55. Clinical and Laboratory Standards Institute. Performance Standards for Antimicrobial Susceptibility Testing. 22nd informational supplement. Wayne: CLSI; 2012. Benwan KA, Sweigh NA, Rotimi VO. Etiology and susceptibility patterns of community- and hospital acquired urinary tract infections in a general hospital in Kuwait. Med Princ Pract 2010;19:440-6. Gupta K, Scholes D, Stamm WE. Increasing prevalence of antimicrobial resistance among uropathogens causing acute uncomplicated cystitis in women. JAMA 1999;281:736-8. Access this article online Quick Response Code: Website: www.jgid.org
DOI: 10.4103/0974-777X.138515
Journal of Global Infectious Diseases / Jul-Sept 2014 / Vol-6 / Issue-3
Copyright of Journal of Global Infectious Diseases is the property of Medknow Publications & Media Pvt. Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
